<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script type="text/javascript">
      let a = 'name';
      obj = {};
      obj.a = 'tom'; //{a:'tom'}
      obj[a] = 'tom'; //{name:'tom'}
      console.log(obj);
    </script>
  </body>
</html>
